(1) Field of the Invention
The present invention relates to bags for use in storing and transporting bulk materials, such as free-flowing powders and granules, farms produce and such like and a process for manufacturing such bags. More particularly, the present invention relates to an improved bag having a material filling opening formed in the top portion thereof and a process for manufacturing this bag.
(2) Description of the Prior Art
In known bags having an opening for filling, formed in the top portion thereof, the filling opening and a top end cover are separately formed and sewn together, and the top end cover is then sewn to a bag proper. Accordingly, known bags have the defect that the sewing operation thereof is very troublesome and the efficiency of the sewing operation is very low.
Furthermore, the top end cover of the known bag is sewn to the bag proper along the entire length thereof to form a seam. As a result, the known bags have an additional defect in that this seam can be broken or loosened by an impact or shock imposed during the operation of piling or loading the bags for storage or transportation. Accordingly, from the viewpoint of carrying out the piling and loading operations without encountering this defect, it has been desired to improve the quality of these bags.